Fluid reservoir for a spray gun with a ventilation device

The invention relates to a flow cup for a spray gun, which has a material outlet which is designed for direct and/or indirect connection to a spray gun, the flow cup having a ventilation device through which air can flow into the flow cup in order to equalize the pressure when coating material flows out of the flow cup via the material outlet, the ventilation device comprising a closure element which can be moved between at least one open position, in which air can flow into the flow cup, and a closed position, in which no air can flow through the ventilation device into the flow cup, the closure element having a closure plug which, in the closed position of the closure element, closes a ventilation opening in the flow cup, and provided separately from the ventilation opening is a latching device, in particular a (first) hollow collar, by means of which the closure element can be held in a latching manner at least in the closed position.

A flow cup of this type is known, for example, from DE 10 2004 007 733 A1. The flow cup described therein comprises a cup-shaped container and a cover that can be screwed onto it via a thread. On its upper side, the cover has an outlet port with an outlet opening, which is designed for direct or indirect (by means of an adapter) connection to a spray gun. This is a so-called upside-down flow cup, which is mounted on a spray gun with the cover facing down.

When coating a surface with the aid of the spray gun equipped with the flow cup, coating material, e.g. paint, by virtue of gravity and optionally of a suction effect generated at the nozzle head of the spray gun, flows via the outlet port from the flow cup into the spray gun. In order to ensure pressure equalization when coating material flows out of the flow cup via the outlet port, the bottom of the cup-shaped container is provided with a ventilation valve. The ventilation valve comprises a hollow collar, the wall of which projects perpendicularly outwards from the bottom of the container. A ventilation opening in the bottom of the container is placed so as to be centric in relation to the hollow collar. A plurality of latching ribs are provided on the external circumference of the hollow collar, which are used to hold a cap-shaped closure element in a closed position, in which a centric closure plug of the closure element closes the ventilation opening. The closure element is able to be moved back and forth between the closed position and at least one open position. In particular, this is a snap-in valve.

Flow cups with ventilation devices in the form of snap-in valves of a similar construction have also become known from the documents DE 10 2006 029 802 A1, EP 2 277 628 B1 and EP 1 658 143 A2.

In practice, flow cups with ventilation devices of this type have proven successful. However, the flow cup and in particular the associated ventilation device must meet enormous demands in terms of long-lasting functional reliability, even with repeated opening and closing under the intensive influence of solvents and after prolonged storage of various substances in the flow cup.

Accordingly, one aspect of the invention relates to increasing the functional reliability of the ventilation devices of generic flow cups.

Various embodiments of a flow cup are disclosed herein.

The flow cup according to the invention is characterized in that provided separately on the outside of the flow cup, in particular at a spacing from the ventilation opening and separately, in particular spaced apart from the latching device, is a device which as a centering, retaining and/or guiding device interacts with the closure element.

The latching device is preferably fastened to the outside of the flow cup and not to the closure element. The latching device is designed in particular as a hollow collar which preferably extends perpendicularly to the region of the outside of the flow cup on which it is disposed and/or which projects in relation to the outside of the flow cup. In particular, the hollow collar is embodied so as to be integral to the region of the outside of the flow cup on which it is disposed.

In the case of a more general implementation of the inventive concept, instead of the latching device, a device for holding the closure element at least in the closed position is generally provided, the closure element being held at least in the closed position by means of the device, for example in a form-fitting and/or force-fitting manner.

If the additional device according to the invention already fulfils one of the functions of centering, retaining or guiding, the functional reliability of the ventilation device is increased since any (possibly only temporary) impairment of the other components, in particular the latching device or the sealing plug with regard to one of the functions guiding, retaining or centering, can be compensated for.

The additional device fulfils a guiding function if it also defines or controls the path of movement of the closure element between the closed position and the open position, at least in portions.

The closure element is preferably guided along a rectilinear path of movement between the closed position and the open position. In alternative exemplary embodiments, the closure element can also be guided along a curved path of movement or rotated, turned or tilted in order to convert it from the closed position to the open position and back.

The centering function is implemented by the separate additional device if the latter is designed in such a manner that it can return the closure element to a desired path of movement should it accidentally perform an incorrect movement. In this sense, the centering serves to align the closure element with respect to the cup-proximal components of the ventilation device. In particular, the centering causes the sealing plug to be aligned with respect to the ventilation opening.

The retaining function refers to retaining the coating material contained in the flow cup. In particular, this is a sealing function if the coating material can be retained almost completely.

In the context of the invention, not all three functions have to be performed by one and the same additional device. One device can also be provided for each of the functions, only two of the functions (i.e. two devices each with one function) or even only one device with only one of the three functions.

However, the additional device is preferably designed in such a manner that it can provide all three functions (guiding, retaining, centering).

In the case of a particularly preferred exemplary embodiment, the separate centering, retaining and/or guiding device is designed as a second hollow collar on the outside of the flow cup. The result is a construction of the centering, retaining and/or guiding device that is advantageous in terms of manufacturing technology and is robust.

The second hollow collar preferably extends perpendicularly to the region of the outside of the flow cup on which it is disposed and/or projects in relation to the outside of the flow cup. In particular, the second hollow collar is embodied so as to be integral to the region of the outside of the flow cup on which it is disposed.

In particular, the second hollow collar can provide all three functions (guiding, retaining and centering) by simple constructive means.

In particular, a centering chamfer on the outer opening of the second hollow collar serves to center the closure element. The circumferential wall of the second hollow collar serves to guide the closure element, in that the closure element slides along the circumferential wall (inside or outside) during at least a portion of the closing and/or opening movement. Finally, circumferential contact of the closure element against the circumferential wall of the second hollow collar (inside or outside), in particular in the closed position, can cause coating material to be retained.

The separate centering, retaining and/or guiding device is preferably disposed radially between the latching device, preferably embodied as a first hollow collar, and the ventilation opening on the outside of the flow cup.

In a particularly preferred exemplary embodiment, the closure element has a component which is separate from the closure plug, in particular at a spacing therefrom, and which interacts with the separate centering, retaining and/or guiding device. The sealing plug is one of the components of which the functionality is particularly at risk due to damage, dirt or other impairments. In order for the separate centering, retaining and/or guiding device to be able to have a compensating effect particularly in the event of a functional impairment of the sealing plug, it is advantageous for it to not interact with the sealing plug but with a device separate from the sealing plug.

The separate component is preferably provided with latching means which interact with the latching means on the latching device (first hollow collar) on the outside of the flow cup.

An exemplary embodiment in which the separate component is designed in the form of a third hollow collar is distinguished by manufacturing advantages and a robust design.

In the case of a particularly preferred exemplary embodiment, the closure plug projects axially in relation to the third hollow collar which is disposed on the closure element. This ensures that the sealing plug can still penetrate the ventilation opening to a sufficient depth in order to seal the opening securely and tightly, even if the third hollow collar comes to rest on the outside of the flow cup.

The sealing plug particularly preferably protrudes by a distance in relation to the third hollow collar, which at least almost corresponds to the wall thickness of the flow cup in the region of the ventilation device, whereby a sufficient penetration depth of the sealing plug in the ventilation opening can be ensured, and on the other hand it is prevented that the sealing plug inside the flow cup projects in relation to the inner wall. A protruding stopper tip can interfere with the mixing of coating material in the flow cup and entails the risk that the stopper will be pushed outward by a stirrer, so that the ventilation device will be accidentally opened.

Alternatively or additionally, a protruding stopper tip can be prevented in that the closure stopper has a shoulder which, when interacting with a periphery of the ventilation opening, serves as an axial stop.

The functional reliability of the ventilation device is further increased in that a fourth hollow collar is provided on the outside of the flow cup, which forms the periphery of the ventilation opening, the fourth hollow collar being embodied for centering the sealing plug when the ventilation opening is closed. The outer opening of the fourth hollow collar is preferably provided with a centering chamfer for this purpose.

The fourth hollow collar preferably extends perpendicularly to the region of the outside of the flow cup on which it is disposed and/or projects in relation to the outside of the flow cup. In particular, the fourth hollow collar is embodied so as to be integral to the region of the outside of the flow cup on which it is disposed.

In a preferred variant of the invention, the interaction of the various components takes place in such a manner that the closure element is guided during the movement between an open position and the closed position by an interaction of the first hollow collar on the outside of the flow cup and of the third hollow collar, which is disposed on the closure element, wherein the closure element can also be centered and/or guided at the end of the closing movement by the separate centering, retaining and/or guiding device. In this way, the end portion of the closing movement of the closure element, which is particularly relevant for functionally reliable closing of the ventilation device, is advantageously assisted or secured by the separate centering, retaining and/or guiding device.

In the closed position of the closure element, the separate centering, retaining and/or guiding device preferably fulfils a sealing effect by sealing contact of the third hollow collar with the separate centering, retaining and/or guiding device.

Tilting of the closure element is counteracted particularly effectively in that the end face of the third hollow collar in the closed position of the closure element is disposed in an annular space which is configured between the latching device (first hollow collar) on the outside of the flow cup and the separate centering, retaining and/or or guiding device.

Handling advantages result in the case of a particularly preferred exemplary embodiment if the closure element is designed in the shape of a cap with a cap plate from which the closure stopper and/or a (third) hollow collar project/projects. The cap plate serves as an easily accessible control element.

The cap-shaped closure element is preferably embodied in such a manner that it can also serve as a closure cap for the material outlet of the flow cup.

Material is saved if the closure element is designed in the shape of a cap with a cap plate which is provided with a number of openings and/or which has a centric hollow protuberance that forms the closure plug. The openings in the cap plate can also be advantageous for demolding when the closure element is manufactured in an injection-molding process.

It goes without saying that the closure element of the ventilation device according to the invention does not have to have a single open position and a single closed position. In particular, the ventilation device can be embodied in such a manner that the closure element can be moved between two end positions, the ventilation device being closed in the first end position and being open in the second end position (maximum open position). In the intermediate positions of the closure element, the ventilation device can be closed or open, depending on the design.

A refinement of the invention is characterized by advantageously embodied latching means, in which the third hollow collar, which is disposed on the closure element, is provided with first latching lugs on the external circumference, which interact with the latching means on the latching device (first hollow collar) on the outside of the flow cup, in order to hold the closure element in the closed position, and/or the third hollow collar is provided with second latching lugs on the external circumference, which interact with the latching means on the latching device (first hollow collar) on the outside of the flow cup in order to keep the closure element captive in a maximum open position on the flow cup.

Likewise advantageous latching means result if the latching device embodied as a first hollow collar is provided with an (encircling or segmented) latching edge for the closure element on the outside of the flow cup in the region of its end face on the inner circumference.

In the case of a particularly preferred variant, the flow cup has a material container and a cover that closes the material container in a fluid-tight and releasable manner.

The material outlet, which is designed in particular as an outlet port, is preferably disposed on the material container and the ventilation device is disposed opposite on the cover.

Alternatively, the material outlet, which in turn can be designed in particular as an outlet port, can be disposed on the cover and the ventilation device can be disposed opposite on the bottom of the material container.

The flow cup is a consumable that is preferably (at least partially) made of plastic in an injection-molding method. It is particularly advantageous here if the cover of the flow cup and/or the material container of the flow cup are made in one piece from plastic in a plastic injection-molding method. The closure element is also preferably produced as a one-piece component in an injection-molding method. The closure element can also be produced together with the cover or cup (e.g. connected via a film hinge) in an injection-molding tool.

It is understood that individual additional components such as sieve elements, etc., do not have to be molded together with the cover or the material container, so that the cover or the material container can be regarded as manufactured in one piece.

However, a joint one-piece production is quite conceivable.

The ventilation device is preferably disposed on the outside of a disk-shaped end wall which closes the material container at the front, the end wall being provided with a concavity which extends evenly over the end wall.

Thanks to the uniform concavity, the ventilation device axially projects to a lesser extent in relation to the peripheral region of the end wall, this reducing the space required by the material container. At the same time, the ventilation device is still freely accessible from the outside.

It goes without saying that the concavity is present in the basic state of the material container and not only when a force is applied to the end wall, e.g. by an internal pressure or the like.

In a particularly preferred embodiment, the ventilation means comprises an off-center ventilation opening through the concave end wall, which is offset towards the center of the end wall and is preferably greater than 5% and less than 10% of the diameter of the end wall. In this way, the ventilation device is disposed at least almost centrally on the end wall, but due to the eccentric arrangement of the ventilation opening, the injection point can be chosen as exactly as possible in the middle when producing the end wall in an injection-molding method.

A preferred exemplary embodiment is characterized by good accessibility of the corner region between the end base and a connected circumferential wall of the flow cup, in that the concave end wall adjoins the circumferential wall of the flow cup at an angle of greater than 90°.